The term form-fill-seal (FFS) means producing a bag or pouch from a flexible packaging material, inserting a measured amount of product, and closing the bag. Two distinct principles are utilized for FFS packaging: horizontal and vertical. In a typical vertical FFS machine, for example, a flat web of plastic film is shaped around a bag-forming tube. As the shaped web moves down around the forming tube, the opposing edges of the web are overlapped for either a fin or lap seal. At this point, with the web wrapped around the tube, the web moving vertically down along the bag-forming tube will be sealed. A vertical seal mechanism forms the fin or lap seal to make the web into a tube, and a cross-seal mechanism forms a cross-seal beneath the bag-forming tube to simultaneously seal the top of a filled bag and the bottom of a succeeding empty bag. After sealing the bottom of the succeeding empty bag, the succeeding empty bag is filled with a product dropped through the bag-forming tube.
If the bag is to be reclosable, a fastener is typically attached to the inner surface of the web. The fastener may be continuous and move in the same direction as the web, or the fastener may be divided into individual bag-width segments applied transverse to the direction of web movement. To facilitate operation of the reclosable fastener, a slider may be slidably mounted thereto. The slider engages the fastener's interlocking profiles while moved in one direction, and disengages the profiles while moved in the opposite direction.
Heretofore, it has been proposed to attach the slider-operated fastener to the web as the web moves through the FFS machine. For example, in one proposed technique used on vertical FFS machines, the sliders are mounted to the fastener prior to the bag-forming tube and the slider-operated fastener is subsequently attached to the web as the web moves down the bag-forming tube. In another technique the fastener is attached to the web as the web moves down the bag-forming tube and the sliders are subsequently mounted to the fastener. Such techniques for attaching the slider-operated fastener to the web are closely dependent upon the FFS machine, can adversely affect the machine's efficiency and performance, and require significant modifications to standard FFS machines in order for such machines to handle the sliders and fastener.